1968-1983: Years of Silence and Teaching at the University of Navarre

In 1968, after two years at Granada, Leonardo Polo returned to the University of Navarre, where he taught a variety of courses including history of philosophy, ethics, fundamentals of philosophy, psychology or any other course that required filling in when no other professor was available. Polo also continued working privately on the implications of his philosophical methodology. In 1971 he published the article "The question of extra-mental essence" and in 1972 he finished a 500 page volume titled Transcendental Anthropology, which he did not however publish.

From 1978 until his retirement, Leonard Polo crossed the Atlantic during the summers to give brief courses in various Latin American universities among which were the Pan-American University (Mexico), the University of Piura (Peru), La Sabana (Colombia), and the University of the Andes (Chile). His knowledge and love for Latin America and its circumstances is evident in his essay Liberation Theology and the Future of the Americas, published in 1988.

Through the 1970s and early 1980s, Polo gave a number of undergraduate and graduate courses on a variety of topics. Many of these courses would become integrated into his larger philosophical project and would serve as the basis for publications in later years. It is also during these years, both in Latin America and at Navarre, that students began transcribing notes based on Polo's lectures and then passed them from one to another. At times, these notes would be reviewed and corrected by Polo himself, and would become an important instrument for the development of his own thought and as eventual basis for publications in later years.

Examples of class notes preserved from this period give a further insight into Polo's philosophical activity during these years: investigations on Aristotelian philosophy of nature; Aristotelian philosophical psychology; several courses on the theory of knowledge (engaging especially with Kant, Hegel, Nietzsche); the rational knowledge of God; general psychology; habitual knowledge of the first principles; social justice; natural law; political philosophy; courses on liberation theology; bioethics; philosophy of education; philosophy of science (space and time); ethics; action theory; business sciences; sociology; organizational theory; philosophy of work and technology; philosophy of communication; philosophy of information sciences; philosophy of culture; philosophy of art; esthetics; philosophy of education; and philosophy of history. In addition to this, Polo also taught courses focused on specific currents and periods of the history of philosophy such as nominalism, idealism, contemporary philosophy, and Thomism, as well as specific philosophers including Scotus, Eckhart, Leibniz, Hegel, Kierkegaard, Nietzcshe and Heidegger.